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In order to provide WiFi coverage for a small office area, a Cisco autonomous single-band 1041 (AIR-AP1041N-E-K9) is used, running software version 12.4.25d-JA1. The access point is having a basic configuration for a single SSID with WPA/TKIP + PSK.

Most of the wireless clients are laptops and smartphones. There is also a print server and a handheld computer. All of them can connect to the wireless network without issues and are getting proper service. However, every now and then all wireless clients get unreachable simultaneously for several minutes.

We have checked the RF environment and results were good:

  • RSSI is greater than -60 dBm throughout the whole office area
  • RSSI from surrounding wireless networks is at least 30 dB lower than RSSI from the office SSID
  • Spectrum analysis confirms there are no interferences

We observed the following facts when the issue is happening:

  • All WiFi clients lose connectivity at the same time, while wired devices have no issue
  • The AP is reachable on its management IP address and reports the WiFi clients are still associated
  • All wireless clients recover connectivity as soon as you connect a new client to the wireless network.

The radio interface is getting reset sometimes, but it does not happen when the issue is observed. Last time we found the issue we saw logs for the radio interface getting reset more than one hour ago before the issue.

I thought it could be a bug and have reviewed the list of bugs for this software version but couldn't find anything similar to this issue.

Did you ever face a similar problem? Could you find the root cause for it? What else could I check to narrow down the cause of the issue?

Daniel Yuste Aroca
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    you should do a show logg and provide that to us. it may tell you if the radios are being reset or not – knotseh Jul 11 '13 at 02:37
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    "All wireless clients recover connectivity as soon as you connect a new client to the wireless network" is the most interesting symptom described. Along with the `show log` that @hestonk indicated, I would try some debugs like `debug dot11 dot11radio ....` – generalnetworkerror Jul 11 '13 at 08:37
  • "The interface DotRadio 0 does reset from time to time, but is does not happen by the time the issue is observed." Could you clarify: doesn't happen close to the start of the problem, the end of the problem, or at no time close to the problem? – YLearn Jul 11 '13 at 17:13
  • Last time we observed the issue we could see log entries for the interface DotRAdio 0 getting reset, but it was more than one hour before the issue happened. I have edited the question adding this information. – Daniel Yuste Aroca Jul 15 '13 at 20:06
  • "The radio interface is getting reset sometimes, but it does not happen when the issue is observed. Last time we found the issue we saw logs for the radio interface getting reset more than one hour ago before the issue." Is the clock on the AP accurate? Kind of sounds like the AP may be in a different timezone – emynd Jul 16 '13 at 13:55
  • The AP clock is accurate, showing the right time. – Daniel Yuste Aroca Jul 16 '13 at 19:29
  • Did you also measure the spectrum while the issue is occurring? Could be something as simple as a leaky microwave. Even though reconnecting a new client fixes the issue makes it seem like a bug, the bug might be triggered by something physical. – JelmerS Jul 18 '13 at 14:26
  • @JelmerS As explained in the body of the question, spectrum analysis was performed for several days in customer premises and no interferences were detected when the issue was appearing. Furthermore, as customer is having a couple of microwaves in the office, we forced the AP on channel 11 and started the microwaves: we could see the interference from microwaves but it was not disrupting wifi client connectivity – Daniel Yuste Aroca Jul 23 '13 at 19:55
  • You say that clients are losing "connectivity". Does this actually mean that their associations drop, or could it be a higher-layer issue? (You say that the associations are still listed, but do the clients agree?) – chrylis -cautiouslyoptimistic- Aug 08 '13 at 09:01
  • Does it only happen when someone heats up a burrito in the work Microwave? Is there damage to the Microwave oven's shielding? – alex_da_gr8 Aug 08 '13 at 06:33

1 Answers1

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We upgraded firmware on the AP to version 12.4.25d-JA2 and the problem has disappeared. It has been working for one month withouth any issue.

Daniel Yuste Aroca
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